Ⅰ.单句语法填空
1．How did he react ______ your answer?
【答案】 to
2．The athlete failed ______(keep) his balance in his new shoes while skating，and fell to the ground.
【答案】 to keep
3．Wang Kai is studying hard，______(aim) at passing the College Entrance Examinations of 2015.
【答案】 aiming
4．When ______(heat) ，metals expand.
【答案】 heated
5．That year his total income，with his reward added ________， added up to 12,000 yuan.
【答案】 to
